6.8

CVE-2025-49222: Mattermost Shared Channel Upload Type Validation Bypass

Analyzed
AliasesGHSA-q453-638c-h4mrGO-2025-3904
Published 21-08-2025Last modified 21-08-2025

Vulnerability summary

CVE-2025-49222 is a medium (CVSS 6.8) vulnerability in mattermost. EPSS estimates a 0.30% chance of exploitation in the next 30 days, higher than 22.9% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 6.8, network access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
6.8/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.30%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Timeline

  1. 21-08-2025
    PublishedVulnerability first disclosed.
  2. 21-08-2025
    Last modifiedVulnerability information updated.

Description

Mattermost versions 10.8.x <= 10.8.3, 10.5.x <= 10.5.8, 9.11.x <= 9.11.17, 10.9.x <= 10.9.2, 10.10.x <= 10.10.0 fail to validate upload types in remote cluster upload sessions which allows a system admin to upload non-attachment file types via shared channels that could potentially be placed in arbitrary filesystem directories.

CVSS metrics

3 scores · 3 sources · 1 version

EPSS trend

Probability

0.30%

Chance of exploitation in the next 30 days

Percentile

23%

Versus all other CVEs

30-day change

No change 0.00 pp

From 0.30% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: network-reachable, administrative account, no user interaction (CVSS vector). Other conditions: not stated in public data.

Github.com/mattermost/mattermost-server2 products
  • v5≤ 5.39.3 | All versions (No fix recorded)
  • v6≤ 5.7.2 | All versions (No fix recorded)
Mattermost2 products
  • mattermost≥ 10.8.0, ≤ 10.8.3 | ≥ 10.5.0, ≤ 10.5.8 | ≥ 9.11.0, ≤ 9.11.17 | ≥ 10.9.0, ≤ 10.9.2 | 10.10.0
  • mattermost_serverEOL≥ 9.11.0, < 9.11.18 | ≥ 10.5.0, < 10.5.9 | ≥ 10.8.0, < 10.8.4 | ≥ 10.9.0, < 10.9.3 | 10.10.0
Github.com/mattermost1 product
  • mattermost-server≥ 10.8.0, < 10.8.4 | ≥ 10.5.0, < 10.5.9 | ≥ 9.11.0, < 9.11.18 | ≥ 10.9.0, < 10.9.3 | ≥ 10.10.0, < 10.10.1 | ≥ 10.10.0+incompatible, < 10.10.1+incompatible
Github.com/mattermost/mattermost/server1 product
  • v8< 8.0.0-20250708173752-d6b35c41f0ae5 | All versions (No fix recorded)

4 vendors · 6 products

References

5 links